Transcript for Squirrels
On-screen: Squirrels created by the Arizona Game and Fish Department (www.azgfd.gov)
Speaker: The Abert’s squirrel is 18 to 24 inches long, with a gray body, a reddish back, a white belly, and a dark tail with white sides. Their front forepaws are well-adapted for life in the forest. The long, padded toes have sharp claws. They are very nimble and flexible. Long tufts of fur on the tops of their ears have given them a nickname—the tassel-eared squirrel.
Sometimes, they will perch motionless on a stump, sitting upright and surveying the surrounding terrain. But most of the time, they are in motion—a running, bounding blur flitting through the forest, rarely out of sight of a pine tree. In fact, their lives are totally dependent on the Ponderosa pine tree, using it for food, shelter, and open space. Here is an Abert’s squirrel nibbling away on a forest tree—the juicy, sweet seeds hidden inside the scales of a pine cone.
They nest in the trees too, favoring a mass of intertwined twigs infected by dwarf mistletoe. The branches of the tree serve as an elevated highway where they could speed around, jumping up to 7 or 8 feet between interlocking branches. Depending on the abundance of food sources, their territory can cover 6 to 24 acres.
This dependency on the Ponderosa pine tree also puts them at risk in the event of a forest fire, the kind of hot, blazing fire that burns up the high boughs of the pine trees. After a fire of this magnitude, the trees are stripped of their interlocking canopy, leaving little opportunity for the Abert’s squirrel to find food or shelter. Fire, though, is a natural part of a forest life cycle and can be expected to happen.
In the forest just north of Flagstaff, steps are being taken to avoid a big, hot forest fire like the ones we’ve seen recently in other parts of the state. The Forest Service and other land managers are implementing fuel reduction treatments—a policy which includes thinning or cutting out some trees—and prescribed burns. The goal is to protect homes from fire in forested areas. The Arizona Game and Fish Department is interested in the effects on wildlife resulting from these treatments. Catherine Wightman is a researcher for Game and Fish.
Catherine Wightman, AZ Game & Fish: There’s been a big push to reduce the fuels around communities. We’re really concerned about communities burning up in catastrophic wildfire. And so the Forest Service is going to be doing a lot of thinning and fuels reduction treatments in the wildland urban interface, so in those areas right around Flagstaff. And we believe that we can protect communities and still maintain habitat for wildlife.
Speaker: Part of this forest management plan prescribes small, smoldering fires to be purposely set among the pine needles and debris covering the forest floor. The idea is to burn a little now, clearing away some of the dry brush. The fire stays low, avoiding the upper reaches of the trees where the Abert’s squirrel lives. In other areas, the tree canopy will be opened up, allowing more sunlight to get through, promoting the production of grasses, forbs, and pine cones. The overall goal is to create what’s called a mosaic effect—some dense canopy and some open spaces, some burned areas, and other areas untouched.
Catherine Wightman: We’re concerned that we’re going to be reducing a lot of the squirrel habitat. And so in this area, we’re hoping to be able to put on the ground a mosaic prescription that squirrels really seem to respond to. And that’s patches of that really dense canopy forest and then patches that are more open.
Speaker: Now, to see just how this forest management process affects the Abert’s squirrel, a primary inhabitant of the Ponderosa pine, Game and Fish biologist Catherine Wightman and Fenner Yarborough are conducting research.
Fenner Yarborough, AZ Game & Fish: We’re at Fort Valley in Flagstaff. We’re setting traps. We have 160 traps. So we’re baiting them with peanuts, opening them early this morning and going to leave them open all day, and then come back about 5:30 or 6:00 tonight and check them and see if there’s any squirrels in there.
Speaker: The research methodology involves trapping squirrels and then fitting them with these technical marvels—a small locator beacon that fits around the squirrel’s neck. Researchers can track the squirrels’ movements with these receiver antennas. Norris Dodd, with the Arizona Game and Fish Department, has been trapping squirrels for a long time and explains the process.
Norris Dodd, AZ Game & Fish: It’s a 12-line grid, 12 traps on each line, so we end up with 144 traps spaced about 70 meters apart. The whole area is about 150 acres. And because I have to have a crew of trappers walking the lines, we need to make sure that it’s something they can follow without getting lost. Everything is established on a compass line. And we use this hip chain to go ahead and measure accurately between the different trap line.
Speaker: Norris conducted his studies on squirrels in the mid 1990s. The ongoing drought is believed to have affected their population. There just doesn’t seem to be as many these days as there were 10 years ago.
Catherine Wightman: You had squirrel densities that were three or four times higher than what we found so far. We’re really hoping that we’ve had about 18 months of pretty decent wet weather, and so we’re hoping that the squirrel population will respond to that. And we’ll see next spring if, in fact, it did.
Speaker: The traps are simple, spring-loaded devices that do not harm the squirrels. Each morning, Catherine and Fenner load up with a bucket full of peanuts and walk the trap lines, baiting their prey.
Fenner Yarborough: We got peanuts in the bucket that we use for baiting. We try to put a handful in the back of the trap and then some around the front, and a little bit of trail going in to hopefully entice them into the trap.
Speaker: Each trap is partially covered with sticks to provide some cover for the animal inside.
Fenner Yarborough: Even though we do put some shade, I think the high temperature today is supposed to be 58, so they won’t overheat or get too cold during the day or anything like that.
Speaker: Then, later in the afternoon, Catherine and Fenner return to check the traps. Empty traps are sprung so that an animal will not get caught overnight.
Catherine Wightman: It gets cold enough in Flagstaff that we can’t leave them open overnight. So we check them as close to dark as we can, and close them at night to make sure nothing gets in there until morning. And then, we’ll come back out and set them again.
Speaker: It’s simply a matter of walking from one trap to the next, looking inside for an animal, and if there is none, using a long pole to flip the trap mechanism. You get your exercise with this type of work.
Fenner Yarborough: These traps are 50 meters apart, and we have four grids in two different sites. So, we pretty much walk about 6 miles a day, lugging around buckets of peanuts. And most of the time, we end up working at night, so we’re trying to find tiny, little pin flags in the dark with flashlights. So, it is tougher work than most people think.
Speaker: Trap after trap is empty. It’s not that easy to catch a squirrel. Researchers have to be very diligent to get a sample size large enough to make the study relevant.
Fenner Yarborough: We’re just going to keep trapping and keep seeing what we can do, and maybe they’ll get used to the traps a little more and start going in them. And we’ll just keep plugging away, and hopefully, we’ll have better luck.
Speaker: Finally, we walk up on a trap with a small, furry rodent inside. Ah, but it’s the wrong kind of squirrel for this study. This is a common ground squirrel, not the Abert’s.
Catherine Wightman: OK, no biting.
Speaker: The trapdoor is opened.
Catherine Wightman: Go on. You’re free. You’re free.
Speaker: And he runs away. Other traps yield Steller’s jays.
Fenner Yarborough: Go.
Speaker: Then, one trap has captured an Abert’s squirrel. He has to be anesthetized before the radio collar can be attached. This is done by placing the entire trap inside a bag, then adding a pouch filled with knockout drugs to put him to sleep. These are the same drugs your vet uses on your pet. Once he’s out, researchers have to work fast, attaching the collar loose enough so that it doesn’t restrict movement, but tight enough not to fall off. Then, after a brief recovery period, he’s released back into the wild. Now, his habits can be tracked with the radio equipment.
Researchers are hoping to learn more about the squirrels’ movements after the forest has been treated. For example, will the squirrels move out of the treated areas or will they stay and just use the untreated areas? How do they utilize the new space created when fire clears out brush and debris? This data will be tracked over time and be compared to squirrels in areas where no treatment has been done. It will make it possible for researchers to better understand the Abert’s squirrel.
Fenner Yarborough: Around here in Flagstaff, they’re being really proactive with prescribed fires and that type of thing. So, we really want to monitor squirrel populations and other wildlife populations to see the effect of prescribed burns on the animals.
Speaker: Forest fires are a fact of life. As people move and build homes near wooded areas, the pressure to protect these homes from wildfires increases. Researchers like Catherine and Fenner are looking for a balance, a balance between protecting houses from fire and maintaining habitat for wildlife.